Co-stars Bella Thorne and Patrick Schwarzenegger had to get close fast while filming “Midnight Sun.” During a rare respite from the Vancouver rain on the second day of filming, director Scott Speer put the two actors in a sailboat to film one of the heaviest scenes of the movie, and hoped for the best.

“We were both freezing as f—, because I was just in a little dress and (Schwarzenegger) was in a t-shirt,” Thorne said. “So we were really holding each other, we were both kind of shaking and then we were like ‘Hey, this is kinda nice.’”

In the film, Thorne and Schwarzenegger play a pair of star-crossed teenage lovers. Thorne’s character, Katie Price, is afflicted by a genetic disease called xeroderma pigmentosum that causes extreme sensitivity to sunlight. She is forced to spend her days inside, playing guitar and watching Charlie Reed, played by Schwarzenegger, from her window. When Katie and Charlie finally meet under the cover of night, a blissful and fleeting summer romance ensues.

Source: Ed Araquel Bella Thorne in “Midnight Sun.” Thorne’s character in the movie suffers from an illness that prevents her from being outside in the sun.

The film will premiere on March 23.

Speer said he was “blown away” by Thorne and Schwarzenegger’s on-screen chemistry. Little did he know, the two had been conspiring since their auditions.

Schwarzenegger said he and Thorne were friendly before the audition process. When he was called in for a chemistry read with Thorne, he texted her asking if they could meet up beforehand.

“It helped me so much because this was one of my first (lead roles), and a chemistry read is kind of nerve-wracking,” Schwarzenegger said. “To do it with someone you’re friends with could be even more awkward or embarrassing, but for her to come and meet me hours before. … It really helped me be comfortable, and I can’t thank her enough for it.”

Schwarzenegger said his chemistry with Thorne grew as the two became closer on set. Aside from bonding over their shared misery in the Vancouver cold, he said Thorne hit his “sweet spot” by baking him lots of food behind the scenes.

With “Midnight Sun” as his first major film, Schwarzenegger said he worked closely with Speer to find an emotional connection to his character. He said Speer helped him navigate his initial discomfort with some of the heavier scenes.

When filming a particularly difficult scene in which Charlie hears one of Katie’s songs playing on the radio, Schwarzenegger said he was blindsided by how emotional he became. Authentic moments like this brought “something really special” to the film, Speer said.

Speer approaches every film he directs with music in mind, he said. He said the soundtrack of “Midnight Sun” drives the emotions of the story and hopefully speaks to the audience.

“Whenever you use music, I feel like you can speak to someone in a way articulation won’t accomplish,” Speer said. “I think both Pat and Bella were really on board with making those moments happen.”

However, Thorne was initially resistant to the idea of singing in the movie.

“For a long time I said I was never going to sing again,” Thorne said. “But I knew that that song had to be there. This is that character’s art; music is such a big part of her. If I wanted to have Katie, I couldn’t be choosy. I had to have all of her.”

After much convincing from Speer — Thorne canceled on him four times before finally coming into the recording studio — Thorne recorded the song that was originally written into the movie, as well as several songs for the soundtrack.

Thorne said she is grateful to Speer for leading her back to music. She said music is “the universal language,” so it is fitting that it plays an important role in “Midnight Sun.”

Weinberg freshman Ally Snow said she is excited to see another tearjerker love story that all of her friends will enjoy. She said the movie trailer reminded her of “A Walk to Remember,” one of her all-time favorites.

Speer said he hopes “Midnight Sun” will be a classic romance movie that will touch audiences. He said while viewers may not relate directly to Katie’s story, they will relate to the experience of having a first love.

“I love great love stories,” Speer said. “The best part about a good love story is you get swept up in it. If you’ve been in love, you resonate with it, If you’re going to be in love, it’s like coming attractions. And if you were in love, you remember that time. It has that universal pull.”